Caledonite is a striking lead-copper sulfate-carbonate mineral known for its vibrant deep blue-green to teal color. It is most frequently found as small, distinct prismatic crystals or crusts in the oxidized zones of lead-copper ore deposits, often associated with linarite.

Hardness

2.5-3

Mohs

Luster

Vitreous to resinous

Streak

Pale green

Transparency

Translucent to transparent

mineralrare

Caledonite

Hardness: 2.5-3
Luster: Vitreous to resinous
Streak: Pale green
Transparency: Translucent to transparent

Is this caledonite?

5-step field check

Run through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.

1
Test the hardness
Try to scratch caledonite with a known reference. Caledonite sits at Mohs 2.5-3, softer than the next harder reference, harder than the previous one.
2
Check the streak
Drag the specimen across an unglazed porcelain plate. Streak: pale green.
3
Read the luster
Hold the specimen under a strong light. Luster: vitreous to resinous.
4
Match the color range
Compare against the expected color range: blue, blue green, green, dark green.
5
Look at form & habit
Crystal system: orthorhombic. Typical habit: prismatic, radial, striated.

Often confused with

Caledonite vs. its common look-alikes, and how to tell them apart in the field.

How to tell apart: Luster reads vitreous to resinous on Caledonite and adamantine to vitreous; silky if fibrous; dull to earthy if massive on Malachite.

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Often found alongside caledonite

Minerals reported to co-occur with caledonite. Spotting these in float or country rock is a strong cue you are in the right ground.

All properties

Chemical formula: Cu₂Pb₅(SO₄)₃(CO₃)(OH)₆
Mohs hardness: 2.5-3
Density: 5.6-5.76 g/cm³
Colors: Blue Blue green Green Dark green
Streak: Pale green
Luster: Vitreous to resinous
Transparency: Translucent to transparent
Crystal system: Orthorhombic
Crystal habit: Prismatic, radial, striated
Cleavage: On {010}, perfect; on {100} and {101}, imperfect
Rarity: Rare
Uses: Collector
Host rock: An uncommon secondary mineral in the oxidized portions of Pb–Cu deposits

Where rockhounds find caledonite

Classic worldwide localities

Mammoth-St. Anthony mine, Tiger, Pinal Co., in the Rowley mine, near Theba, Maricopa Co., Arizona, USA
Mex-Tex mine, near Bingham, Hansonburg district, Socorro Co., New Mexico, USA
Blue Bell mine, near Baker, San Bernardino Co., at the Chance mine, Chidago Canyon, Mono Co., and from Cerro Gordo, Inyo Co., California, USA
Leadhills, Lanarkshire, and Wanlockhead, Dumfriesshire, Scotland
Red Gill and other mines, Caldbeck Fells, Cumbria, England
Preobrazhensky mine, Beresovsk, near Yekaterinburg (Sverdlovsk), Middle Ural Mountains, Russia

Field-hunting tip

Where it forms: An uncommon secondary mineral in the oxidized portions of Pb–Cu deposits. If you start seeing cerussite, anglesite, leadhillite in float, you are in the right ground. Typical habit: prismatic, radial, striated. Train your eye for that shape before scanning the outcrop.

Common questions

How do you identify caledonite?+

Mohs hardness is 2.5-3. Luster: vitreous to resinous. The streak is pale green. Common colors include blue, blue green, green, dark green.

Where is caledonite found?+

Notable localities include Mammoth-St. Anthony mine, Tiger, Pinal Co., in the Rowley mine, near Theba, Maricopa Co., Arizona, USA; Mex-Tex mine, near Bingham, Hansonburg district, Socorro Co., New Mexico, USA; Blue Bell mine, near Baker, San Bernardino Co., at the Chance mine, Chidago Canyon, Mono Co., and from Cerro Gordo, Inyo Co., California, USA; Leadhills, Lanarkshire, and Wanlockhead, Dumfriesshire, Scotland; Red Gill and other mines, Caldbeck Fells, Cumbria, England.

Is caledonite safe to handle?+

Caledonite contains copper and lead. Contains lead and copper. Wash hands thoroughly after handling and avoid inhaling dust or powder.

What rocks look like caledonite?+

Caledonite is most often confused with Linarite, Brochantite, Malachite. A quick hardness test and a streak check separate the look-alikes faster than color alone.

What minerals are found with caledonite?+

Caledonite commonly co-occurs with Cerussite, Anglesite, Leadhillite, Brochantite, Linarite, Azurite. Spotting any of these in float or country rock is a useful trip signal.

What kind of rock does caledonite form in?+

Where it forms: An uncommon secondary mineral in the oxidized portions of Pb–Cu deposits. Working float back to the host body is the standard way to chase a fresh occurrence.

What is caledonite used for?+

Caledonite is used in collector.

Find caledonite on the map

RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.